Study on the Vibration Mechanism of Different Cutting Modes in Shallow Tunnel Excavation under Thermal Explosion Loading

As urbanization develops, China has become the largest market in urban subway construction. The vibration induced by subway tunnel excavation blasting critically threatens the structural integrity and human safety in overlying buildings. To address this, this study pioneers a comparative experimental analysis of two damping systems under thermal explosion loading in shallow metro tunnels. These two damping systems are large-diameter empty-hole cutting (LDC) and single-stage wedge cutting (SWC), respectively. Crucially, our work demonstrates that LDC reduces peak vibration velocity by 58-59% compared to SWC, directly correlating the cavity size with vibration intensity (PPV is positive correlation with cavity volume). Furthermore, a detailed analysis and explanation of the damping mechanism are also conducted using numerical simulation and classical theory. These findings offer a validated thought for vibration control technology for tunnel blasting. The research results provide a "revolutionizing infrastructure technology" for urban tunnel projects in vibration-sensitive environments under China's high-quality urban development strategy.